Chair with double pivot spring assembly

ABSTRACT

1,011,267. Adjustable back-rests. C. W. CHANCELLOR. Feb. 20, 1963 [Feb. 21, 1962], No. 6814/63. Headings A4J and A4U. An auxiliary back-rest 42 of a chair, which is located in an opening or recess 44 of a main back-rest 26, is vertically adjustable in the opening or recess 44 and is pivotally mounted about a transverse axis. The chair also includes adjustable biasing means urging the auxiliary backrest to pivot to a foremost position, and adjusting means to alter this foremost position. The lower end of a support arm 48 which carries the auxiliary back-rest 42 is mounted for vertical adjustment on a mounting plate 96 by means of a bolt 100 extending through the arm 48 and a slot in the plate 96, the arm 48 also has a pair of ribs interlocking with corresponding grooves on the plate 96. A U-shaped support 106, which is pivotally secured to rails 50, 52 attached to the seat 24, is connected to the plate 96 by rivets 108 and by a turnbuckle assembly 112. By adjusting the turnbuckle assembly 112 the angular position of the back-rest may be varied. The adjustable biasing means comprises a compression spring 138 acting between the U-shaped support 106 and an adjustable handwheel 142 in screw-threaded engagement with a rod 128 which extends through the spring 138 and is attached to a plate 134 extending between the rails 50, 52. The chair described is a vertically adjustable swivel chair which can also pivot about a transverse pivot pin 76. Two springs 94 are connected to the chair frame to resist rearward pivotal movement and by rotating a handwheel 88 the compression on the springs can be varied.

June 11, 1963 Filed Feb. 21, 1962 c. w. CHANCELLOR, JR 3,093,413

CHAIR WITH DOUBLE PIVOT SPRING ASSEMBLY 2 Sheets-Sheet 1 Char/es W. Chancel/or, J

INVENTOR.

\ l2 l6 Maud \n BY gnaw J1me 1963 c. w. CHANCELLOR, JR 3,093 413 CHAIR WITH DOUBLE PIVOT SPRING ASSEMBLY 2 Sheets-Sheet 2 Filed Feb. 21, 1962 1N VENTOR.

United States Patent 3,093,413 CHAIR WITH DOUBLE PIVOT SPRING ASSEMBLY Charles Chancellor, Jr., Box 15, Midland, Tex. Filed Feb. 21, 1962, Ser. No. 174,729 13 Claims. (Cl. 297-484) The present invention generally relates to novel improvements in chair constructions and more particularly to improvements in the supporting assembly for an ofl'lce chair of the swivel type.

Swivel chairs such as those employed in ofiices may be rotated about a generally vertical axis and also pivoted about a horizontal axis located below the seat. An adustable spring assembly is employed to resiliently retain the chair seat and back in a desired position. Such chairs have a rigid seat and back assembly with there also normally being provided arrnrests. It is the primary object of the present invention to provide such a chair with an auxiliary backrest which is movably disposed within an opening provided therefor in the normal backrest which is rigid with the seat together with a double pivot spring assembly for supporting the rigidly asso ciated chair seat and backrest and resiliently supporting the auxiliary backrest independently of the spring support for the rigidly associated chair seat and backrest.

Another important object of the present invention is to provide a positive action double pivot spring assembly for a chair in which the pivots operate independently of each other and in which the spring is associated with each pivot independently thereby enabling independent adjustment and variation of the supporting characteristics of each spring assembly whereby the rigid chair seat and back assembly may be pivoted about one horizontal axis while the auxiliary backrest may be pivoted about a second pivot spaced rearwardly from the pivot axis of the chair seat and back rest whereby the auxiliary backrest may provide a different characteristic of support for the lower central region of the back of an occupant of the chair thereby providing more adequate and comfortable support for the person occupying the chair.

Another important object of the present invention is to provide a chair with a positive action double pivot spring assembly incorporated into the iron structure thereof in which the overall size of the iron structure is retained substantially the same with all adjustments being readily accessible and which is yet simple, in construction, easy to use, effective for providing comfortable support and generally inexpensive to manufacture.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

' FIGURE 1 is a front view of a chair incorporating the positive action double pivot spring assembly of the present invention;

FIGURE 2 is a side elevational view of the chair;

FIGURE 3 is an enlarged top plan view of the spring assembly illustrating the association of components thereof;

FIGURE 4 is a longitudinal, vertical sectional view taken substantially upon a plane passing along section line 44 of FIGURE 3 illustrating further structural details of the spring assembly; and

FIGURE 5 is a rear elevational view of the spring assembly illustrating the mounting plate forattachment of the support arm for the auxiliary backrest.

Referring now specifically to the drawings, the numeral generally designates a chair which incorporates the principles of the present invention therein which chair includes a base generally designated by the numeral 12 supported on conventional caster wheel assemblies 14 and which includes four radially extending members 16. The base 12 is of conventional construction and form-s no particular part of the present invention. A swivel assembly generally designated by the numeral 18 is connected to the base 12 and includes a vertically threaded rod 20 for adjustable engagement with an adjustment sleeve 22 which provides for vertical adjustment of the rod 20 and also for rotation thereof about a vertical axis.

The chair 10 includes a rigid chair seat 24 and a rigid backrest 26 that is rigidly connected to the rear of the chair seat 24. Armrests 28 of generally L-shaped configuration rigidly interconnect the central portion of the side edges of the chair seat with the central portion of the side edges of the backrest 26. The chair seat 24 is provided with a cushion 30 thereon, the back rest 26 is provided with a cushion 32 and the armrests 28 are provided with cushions 34. The specific details of construction insofar as the materials are concerned may vary. For example, a metallic construction may be used with the cushioning bonded thereto in any suitable manner such as employed in presently available ofiice chairs. Further, the swivel. assembly 18 which enables vertical adjustment and rotation about a vertical axis is conventional and forms no part of the present invention except in its association with the chair and the base for accomplishing vertical height adjustment and enabling swivelling of the chair about a vertical axis.

The essential parts of the present invention are incorporated into the spring assembly generally designated by reference numeral 40'and which is specifically illustrated in FIGURES 3-5. The spring assembly 40 is for the purpose of supporting the rigid chair seat 24 and backrest 26 for pivotal movement about a horizontal axis and also for supporting an auxiliary backrest 42 which is received in an opening or recess 44 formed in the rigid backrest 26. The auxiliary backrest 42 may also be of metallic construction with a cushion 46- provided thereon and may be disposed in a plane slightly projecting outwardly from the surface of the cushion 32 on the rigid backrest. Also, the auxiliary backrest 42 is supported on a support arm 48 by any suitable means. The auxiliary backrest 42 may be pivotally mounted on the upper end of the supporting arm 48 thus enabling the auxiliary backrest to conform with and engage the lower portion of the back of an occupant of the chair, thus providing support for the small of the back for rendering the chair more comfortable.

In order to properly support the auxiliary cushion or backrest 42 as well as the rigidly associated seat 24 and backrest 26, the spring assembly 40 includes a pair of elongated side rails 50 and 52 which generally are parallel to each other and include upwardly extending end portions 54 terminating in outwardly diverging ends 56 which are fastened to the chair seat 24 in any suit-able manner such as by bolts, rivets or the like designated by numeral 58 thus rigidly affixing the two rails 50 and 52 to the chair seat.

The upper end of the threaded rod 20 is provided with a reduced extension 60 extending through the big ht portion 62 of a U-shaped member 64 and also extending through the bottom 66 of a box member 68- which also is provided with a forward end wall 70. The top end of the reduced extension 60 is enlarged as at 72 for retaining the U-shaped bracket 64 and the box member 68 in assembled condition on the top end of the threaded rod 20 while enabling swive'lling movement of the components in relation to each other.

member 68 are received between the depending flanges -74 of the side rails 50 and 52 respectively and the components are interconnected by a transverse pivot bolt or pin 76 having headed ends thus retaining the rails 50 and 52 attached to the threaded rod 20 but enabling pivotal movement of the rails "about a horizontal axis defined by the pivot bolt 76,

Rigidly aflixed to and extending transversely of the vertical flanges 74 of the rails 50 and 52 is a plate 78 having a slot 80 formed in the bottom thereof. The plate 78 is normally disposed in substantially parallel relation to the end Wall 70 of the box member 68.

Extending forwardly from the end wall 70 of the box member 68 is an elongated rod 82 which is received in the slot 80 and which is rigidly aflixed to the end wall 70 by virtue of the headed end 84 thereof being welded or otherwise afiixed to the end wall 70. The outer end portion of the rod 82 is threaded as at 86 and threadedly receives an adjusting hand wheel 88 which has the inner surface thereof rotatably engaging a transverse spring seat member 90 which is also slidably disposed on the rod 82. The outer end portions of the spring seat plate 90 are recessed as at 92 for forming a seat for the ends of a pair of parallel coil springs 94 which has the other ends thereof engaged with and attached to the plate 78 in any suitable manner so that the springs 94 will bias or urge the plate 78 toward the plate 70 on the box member 68 thus urging these two members into parallelism and resiliently resisting rearward pivotal movement of the rails 50 and 52 about the transverse pivot pin 76. By rotat- 'ing the hand Wheel 88, the compression on the springs 94 may be varied thereby varying the resilient resistance to pivotal movement of the chair seat and backrest in a rearward direction about the axis of the pivot pin or shaft 76. h

At the rear of the rails 50 and 52, the spring asser'hbly 40 includes a mounting plate 96 for the support arm 48 of the auxiliary backrest 42. The mounting plate 96 is inclined and provided with a slot 98 receiving a bolt 100 therethrough and which also extends through the supporting 48 for adjust-ably securing the arm 48 in position on the mounting plate '96 thus enabling the auxiliary backrest 42 to be accurately positioned in relation to the opening 44 provided therefor.

The mounting plate 96 is provided with a pair of grooves 102 therein for rigidity and for interlocking engagement with corresponding ribs on the support arm 48. Also, the side edges and the top edge of the mounting plate 96 are inturned as [designated by numeral 104 for rigidity and also for connection with a U-shaped support member or bracket 106 which tapers in depth from the forward end to the rear end with the vertical side walls of the U-shaped support member 106 being attached to the inturned edges 104 by fasteners such as rivets 108. The forward upper corners of the side walls of the U-shaped support 106 are pivotally connected to the depending flanges 74 of the rails 50 and 2 by pivot pins or bolts 110 which may be in the form of rivets or the like thus pivotally connecting the U-shape support 106 to the side rails 50 and 52. For completely rigidifying the U-shape' support member 106 and the mountingplate 98, an adjustable turnbuckle assembly 112 is provided between the lower end of one of the flanges 104 and the lower corner of one of the side walls of the U-shaped support 106. The turnbuckle 112 is secured to the flange 104 by a pivot pin or rivet 114 while the other end thereof is attached to the U-shaped support 106 by a similar pivot pin or'rivet H6. The turnbuckle assembly 112 includes a central threaded member 118 having both left and right hand threads whereby rotation of the threaded member will cause the end sleeves forming the remainder of the turnbuckle to move inwardly or outwardly. The central portion of the threaded member 118 is provided with a spoked hand wheel :120 for enabling adjustment of the angular position of the mounting plate 96 thus enabling adjustment of the auxiliary backrest 42 in relation to the rigid backrest so that the 'mounted rigidly in relation to the seat.

supporting characteristics of the auxiliary backrest may be varied.

The two side walls of the U-shaped support member 106 are interconnected by a bight portion or bottom plate 122 that has a centrally disposed offset portion 124 generally paralleling the horizontal flange of the rails 50 and 52. The ofiset portion 124 is provided with an aperture 126 which receives an elongated rod 128 and has the beaded upper end 132 extending through and afiixed to a transverse mounting plate 134 that has the end portions thereof rigidly 'aihxed to the rear end portions of the side rails 50 and 52 by virtue of fasteners 136 as illustrated in FIGURE 3. Enc-ircling the rod 128 is a coil compression spring 138 and the lower end of the rod 128 is threaded as at '140 and receives a hand wheel 142 having a recess in the top surface thereof forming the seat for the outer end of the compression coil spring 138. The inner end of the spring 138 engages the under surface of the offset portion 124 on the bottom plate 122 of the U-shaped support member 2106 thus urging the rear end portion of the U-shaped support member 106 upwardly about a pivot axis formed by the fastener pins, rivets or bolts 110. Thus, as rearward pressure is exerted on the auxiliary backrest 42, the backrest 42, the support arm 48 and the mounting plate 96, U-shaped support member 106 turnbuckle 1=12 and the components attached thereto will all move simultaneously about a pivot axis defined by the fasteners 110. By varying the position of the hand wheel 142 the resilient resistance of the spring 138 may be varied and by adjusting the hand wheel 120, the normal position of the auxiliary backrest may be varied insofar as forward and rearward position is concerned and by initially adjusting the bolt 100, by manipulating the hand wheel thereon the position of the auxiliary backrest may be set insofar as vertical position is concerned.

With this construction, there is provided an independently adjustable spring assembly for providing a positive action resilient force biasing the components about a double pivot for providing independent control of the re silient characteristics of the rigid seat and backrest assembly and the auxiliary backrest thereby producing a chair which is extremely comfortable and which will also reduce the fatigue of the occupant.

While the present invention has been disclosed in use with a swivel and pivotal type oflice chair or the like, it is pointed out that it is within the purview of this invention to also incorporate the auxiliary backrest into various types of seat assemblies regardless of whether there is a swivel assembly and a pivotal assembly for the chair seat and back.

For example, the auxiliary backrest may be incorporated into an automobile seat backrest in which the seat is mounted rigidly on the vehicle floor insofar as pivotal movement is concerned and the seat back or backrest is In this formof this invention, the requisite size and shape opening is formed in the seat back and the auxiliary backrest is disposed therein and resiliently supported from a suitable support by virtue of the same spring assembly as em 'ployed for supporting the supporting arm of the auxiliary head rest. Such an assembly which does not require pivotal movement of the seat and, of course, does not re quire the auxiliary spring therefor, may be used in conjunction with airplane seats for the pilot andcopilot, bus drivers, truck drivers, automobile operators, passengers or the like and the entire assembly provides a highly comfort-able chair in which the chair back or backrest has the auxiliary backrest incorporated thereinto for providing more adequate support for the lower region of the back.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous .modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention 'as claimed.

What is claimed as new is as follows:

'1. In a chair of the type having a rigidly associated seat and backrest, a supporting base and a swivel assembly for enabling swivelling of the seat and backrest about substantially a vertical axis, that improvement comprising an auxiliary backrest, said auxiliary backrest adapted to engage the lower portion of the back of an occupant of the chair, a spring assembly supportingly engaging the seat and including means enabling the seat to pivot about substantially a horizontal axis, a spring assembly supportingly engaging said auxiliary backrest and enabling said auxiliary backrest to swing about substantially a horizont-al pivot axis spaced from the pivot axis of the seat, said spring assemblies being mounted on a pair of common side rails rigidly afiixed to the sea-t, and means independently adjusting each of the spring assemblies thereby independently varying the resilient resistance of pivotal movement of the seat and auxiliary backrest respectively about their pivot axes.

2. The structure as defined in claim 1 wherein said auxiliary backrest includes a depending supporting arm, said backrest attached to the seat having an opening [therein generally conforming with the auxiliary backrest for receiving the auxiliary backrest and enabling relative movement between the auxiliary backrest and the chair seat and backrest.

3. The structure as defined in claim 2 where-in said spring assembly for supporting the auxiliary backrest includes a mounting plate, said mounting plate having a slot therein, a fastener extending through the slot and the lower end of the supporting arm for the auxiliary backrest thereby enabling adjustment of the auxiliary backrest in relation to the opening provided therefor.

4. The structure as defined in claim 3 wherein said spring assembly for the auxiliary backrest also includes a generally U-shaped elongated bracket having one corner thereof pivotally attached to the side rails, the opposite end of said bracket being pivotally attached to the upper end of said mounting plate, a turnbuckle assembly connected to the end of the mounting plate remote from its point of attachment to the U-shaped bracket, the other end of the turnbuckle assembly being connected to the U-shaped bracket in spaced relation to the pivotal connection between the U-shaped bracket and the rails thereby enabling initial angular adjustment of the mounting plate for orientating the auxiliary backrest.

5. A structure as defined in claim 4 wherein said spring assembly for the auxiliary backrest also includes a transverse plate disposed rigidly between said rails, a depending bolt connected to said plate, said U-shaped bracket having a bottom portion in spaced relation with the plate and receiving said bolt, a compression spring encircling the bolt and having the upper end engaging the bottom surface of the U-shaped bracket. an adjustable hand wheel on the lower end of the bolt and engaging the bottom end of the spring whereby adjustment of the hand wheel may vary the compression on the spring thereby varying the resistance of pivotal movement of the U- shaped bracket about its pivotal connection with the side rails.

6. The structure as defined in claim 5 wherein said spring assembly for supporting the chair seat includes a bracket supported from the base, a transverse pivot shaft interconnecting the said bracket and the side rails for pivotally attaching the chair seat to the base, said chair seat having a depending plate provided with a slot in the lower end thereof, a rigid bolt attached to said bracket connected with the base and extending outwardly through said slot, a spring associated with said bolt, a spring seat slidable on the bolt and engaging the outer end of the spring, the inner end of the spring, engaging said plate for urging the plate into substantially vertical position with the seat being disposed in a horizontal posit-ion, and an adjustable hand wheel on said bolt and engaging the spring seat thereby enabling variation in the compression of the spring for varying the resilient resistance of the spring in resisting pivotal movement of the seat rearwardly about the. pivot shaft.

7. A positive action double pivot spring assembly for oflice chairs having a seat and a backrest movable in relation thereto comprising a pair of rigidly interconnected side rails adapted to be rigidly aflixed to the chair seat, a bracket pivotally attached to the central portions of said rails and adapted to be connected to a supporting base, a transverse plate rigidly affixed to said rails and disposed in spaced relation to the bracket, spring means interconnecting the bracket and the plate for urging the side rails to substantially a horizontal position and resiliently resisting pivotal movement of the side rails in a rearward direction about the pivotal interconnection between the bracket and the side rails, bracket means pivotally attached to said side rails rearwardly of the bracket adapted to be attached to the base and including means for supporting the auxiliary backrest, and spring means interconnecting the side rails and the bracket means for resiliently resisting pivotal movement of the bracket means in a direction that will enable rearward swinging movement of the backrest thereby resiliently retaining the backrest and seat in predetermined angular orientation.

8. The structure as defined in claim 7 wherein said bracket means includes a mounting plate attached to an elongated bracket, said mounting palte adapted to be adjustably connected with the backrest, and adjustable means interconnecting the mounting plate and the elongated bracket for varying the angular position of the mounting plate thereby enabling the backrest to be accurately adjusted in relation to the seat.

9. An auxiliary backrest for use in combination with a stationary seat backrest comprising a cushion adapted to be supported in recess means defined in the seat backrest, a supporting arm for said cushion, said supporting arm being free of the seat backrest, a supporting bracket, means supporting the supporting bracket for pivotal movement about substantially a transverse axis, spring means interconnecting the supporting bracket and the supporting means therefor for varying the resilient supporting characteristics of the supporting bracket, and means rigidly interconnecting the supporting bracket and the support arm.

10. An auxiliary backrest for use in combination with a stationary seat backrest comprising a cushion adapted to be supported in recess means defined in the seat backrest, a supporting arm for said cushion, a supporting bracket, means supporting the supporting bracket for pivotal movement about substantially a transverse axis, spring means interconnecting the supporting bracket and the supporting means therefor for varying the resilient supporting characteristics of the supporting bracket, and means interconnecting the supporting bracket and the support arm, said means connecting the support arm and supporting bracket including a mounting plate and a pivotal connection between the mounting plate and the supporting bracket, and means adjusting the angular orientation of the mounting plate in relation to the supporting bracket thereby adjustably orientating the supporting arm and cushion in position in relation to the front surface of the stationary seat backrest.

11. The structure as defined in claim 10 wherein said means interconnecting the support arm and the supporting bracket also includes slot means in the mounting plate, bolt means extending through the slot means and the support arm for adjustably and rigidly interconnecting the mounting plate and the supporting arm for vertically adjusting the support arm in relation to the mounting plate thereby orientating the cushion vertically in relation to the recess means in the stationary seat backrest.

12. In combination with a seat having a back portion wardly and rearwardly of the back portion of the seat 10 thereby enabling variation in the initial position of the cushion and the resilient supporting characteristics thereof.

13. The combination as defined in claim 12 wherein said means resiliently biasing the cushion forwardly includes adjustable spring means interconnecting the seat and the means mounting the cushion for pivotal movement about a transverse axis, said spring means being located under the seat in concealed position.

References Cited in the file of this patent UNITED STATES PATENTS 180,548 Chichester Aug. 1, 1876 

9. AN AUXILIARY BACKREST FOR USE IN COMBINATION WITH A STATIONARY SEAT BACKREST COMPRISING A CUSHION ADAPTED TO BE SUPPORTED IN RECESS MEANS DEFINED IN THE SEAT BACKREST, A SUPPORTING ARM FOR SAID CUSHION, SAID SUPPORTING ARM BEING FREE OF THE SEAT BACKREST, A SUPPORTING BRACKET, MEANS SUPPORTING THE SUPPORTING BRACKET FOR PIVOTAL MOVEMENT ABOUT SUBSTANTIALLY A TRANSVERSE AXIS, SPRING MEANS INTERCONNECTING THE SUPPORTING BRACKET AND THE SUPPORTING MEANS THEREFOR FOR VARYING THE RESILIENT SUPPORTING CHARACTERISTICS OF THE SUPPORTING BRACKET, AND MEANS RIGIDLY INTERCONNECTING THE SUPPORTING BRACKET AND THE SUPPORT ARM. 